Method of drawing and crimping yarn

ABSTRACT

UNDRAWN OR PARTIALLY DRAWN YARN IS CRIMPED AND DRAWN OR MORE FULLY DRAWN BY KNITTING THE UNDRAWN OR PARTICALLY DRAWN YARN INTO A BODY OF STITCHES, STRETCHING THE BODY OF STITCHES SO AS TO DRAWN THE YARN AND SETTING THE YARN WHILE IT IS IN THE CONFIGURATION OF THE STRETCHEDSTICHES. THE BODY MAY BE A CHAIN OF STITCHES WHICH IS CONTINUOUSLY NITTED, FED INTO THE DRAWING AND SETTING ZONE AND THEN UNRAVELLED FROM ITS LEADING END.

v March 9, 1911 D. A E. MATTINGLY METHOD OF DRAWING AND GRIMPING YARN 2Sheets-Sheet 1 Original Filed Jan. 29, 1968 ,nr i o March 1 D. A. E.MATTINGLY 3,568,278

METHOD OF DRAWING AND CRIMPING YARN Original Filed Jan. 29, 1968 2Sheets-Sheet ,2

United States Patent 3,568,278 METHOD OF DRAWING AND CRIMPING YARN DenisAlbert Edward Mattingly, London, England, as-

signor to The Klinger Manufacturing Company Limited, London, EnglandContinuation oil-application Ser. No. 701,248, Jan. 29, 1968. Thisapplication Feb. 27, 1970, Ser. No. 15,243 Claims priority,-applicationGreat Britain, Jan. 28, 1967, 4,316/67 Int. Cl. D04b 19/00 US. Cl.28-72.16 Claims ABSTRACT OF THE DISCLOSURE Undrawn or partially drawnyarn is crimped and drawn or more fully drawn by knitting the undrawn orpartially drawn yarn intoa body of stitches, stretching the body ofstitches so as to drawn the yarn and setting the yarn while it is in theconfiguration of the stretched stitches. The body may be a chain ofstitches which is continuous- 1y knitted, fed into the drawing andsetting zone and then unravelled from its leading end.

This is a continuation of application Ser. No. 701,248 filed Ian. 29,1968 and now abandoned.

The invention relates to crimping yarn, and more particularly tocrimping thermoplastic yarn or yarn having a thermoplastic component.

According to one aspect of the invention there is provided a method ofproducing crimped yarn comprising the steps of forming undrawn orpartially drawn yarn into a body of yarn having a stitchedconfiguration, stretching the body to draw the yarn, setting bends inthe yarn while the body is stretched, and then unravelling the crimpedyarn from the body.

Preferably, the step of drawing the yarn takes place while the yarn isin a heated condition. This drawing may or may not draw the yarn to itsfullest extent.

The step of stretching the body may be achieved by underfeeding the bodyinto theheating Zone.

The body may be in the form of a chain of looped stitches.Alternatively, the body may be in the form of a knitted fabriccomprising a plurality of rows each made up of a plurality of stitches.

The stitched configuration of the body may be such that'the stitches canbe unravelled from the leading end of the body and the method operatedas a continuous process.

According to another aspect of the invention there is provided apparatusfor producing crimped yarn comprising stitch forming means for formingundrawn yarn into a body of yarn having a stitched configuration, meansfor stretching the body of yarn in the stitched configuration to drawthe yarn, heating means arranged to heat the body of yarn while the bodyis in a stretched condition and means for unravelling the crimped yarn.

The stitch forming means may comprise a single needle, such as alatched, bearded or hooked needle, or may comprise a knitting machineincluding a plurality of needles.

The invention will now be described by way of example with reference tothe accompanying diagrammatic drawing in which:

FIG. 1 shows a general perspective view of a yarn crimping apparatus;

FIG. 2 is an elevation of the opposite side of a part I of the apparatusof FIG. 1;

FIG. 3 is a plan view of part of the apparatus shown in FIG. 2; and

FIG. 4 shows part of a chain of looped stitches.

Referringv now to the drawings, the basic features of the apparatus are,reading progressively along the yarn path'indicated by the chain dottedline in FIG. 1, a yarn supply bobbin 1, a knitting station. 2, feedrollers 3 and 4, a heater 5, feed rollers '6 and 7, feed rollers 8- and9, and a crimped yarn take-up bobbin 10.

The apparatus is mounted in a fixed frameworkwhich is omitted from thedrawing for simplicity. Several separate units can be arranged on asingle elongated framework.

Referring to FIG. 1 in more detail, undrawn yarn 11 passes from thesupply bobbin -1 around a hysteresis tensioner 14 at the knittingstation 2.

The knitting station comprises a needle 17, one end of which is providedwith a hook and'the other end of which is screwed into a crank shaft 18and secured by a locknut, the needle and the crank shaft formingasubstantially straight line. The crank shaft 18 is slidably mountedintermediate its ends in a journal bearing-18A which is mounted on ablock 19 for pivotal movement about an axis transverse to the crankshaft. 'A pulley 21 mounted on a shaft is driven by an electric motor 22via a belt 23 passing around a pulley on the spindle of the motor 22. Acrank wheel 24 is mounted on'sa'id shaft on the opposite side of theblock 19 to the pulley'21. The end of the crank shaft 18, remote fromthe needle is pivotally mounted on the wheel 24 by means of a pin 15 sothat on rotation of the wheel 24 the crankshaft is reciprocated and atthe same time rocked about the pivotal axis of the journal bearing 18Aand the hooked end of the needle moves in an endless path. Attached tothe end of the block 19 is a yarn guide assembly including anaperturedbracket 16 through which the needle moves and on which yarn guides 17Aand 17B are mounted at either side of the hooked needle 17 so as toguide yarn transversely across the path of movement of the book of theneedle.

Yarn isfed to the knitting station via the .tensioner 14, passes throughone turn around the needle and leaves the knitting station in the formof a continuous chain 12 of looped stitches.

The stitching operation is self-starting in'that once the .yarn isthreaded through the guides 17A and '17B, the needle. automaticallypicks-up the yarn and: commences to form stitches in the yarn. It isusually required that the first stitch is formed by manuallyoperating'the crank mechanism while pulling the yarn through the guide17A. In order to form the first stitch the tension in the yarn at theguide 17A is required to be greater than for usual operation.

With the stitching operation already commenced and stitches formed inthe yarn being drawn away from the needle, and the needle near itsextreme rearward position (in relation to the crank mechanism as seen inFIG. 1) the needle begins to move forward and upward simultaneously sothat the end of the needle-lifts over the stitches already formed to itsextreme forward position, and the stitches are now held on the needle-bya loop of yarn: on the shank of the needle. The needle continues fromthis position, as it describes an endless path of generally eggshape, tomove downwards as it moves rearward so that the yarn being fed from theguide 26 enters behind the hook of the needle.

The needle continues rearwards tnd the yarn which was engaged by thehook is drawn through the loop-on the shank of the needle. This loop hasnow moved forward along the shank of the needle and over the hook. Asthe needle continues rearward the loop moves beyond the end of theneedle and is cast-off so forming a next stitch in the yarn. The needlewill then be at its extreme rearward position again, thus completing astitching cycle.

The chain of looped stitches formed by the knitting station is passedthrough a ceramic guide 34 to the rubber surfaced roller 3. The roller 3is urged into contact with the roller 4 by means of a spring 38.

The roller 4 is mounted on an axle 41which carries a driving pulley 44and is driven by the motor 22 via a belt 45, a pulley 46, a pulley 47and a belt 48.

The rollers 3 and 4 positively feed the chain 12 through the guide 34over a guide 50 and into engagement with a heater 5. j

The heater 5 is an electrically heated device which is heated byelectric resistance wires (not shown). The temperature of the heater isthermostatically controlled and an adjusting switch 53 is provided foradjusting the temperature of the device. Two grooves 55 and 56 arearranged along the length of heater so that the chain of stitches 12passes down groove 56 in contact with the heater around a guide 57 andthen up the groove 55.

After leaving the heater 5, the chain of stitches passes through theatmosphere for a suflicient distance to cool and then passes over asmooth steel rod 40 to the rubber surface roller 6 which is urged byspring means (not shown) against the roller 7. The roller 7 is attachedto a driving pulley 59 driven by the motor 22 via a belt 61, shaft 72,pulley 47 and belt 48.

Thechain 12 is wound a number of times around the rubber covered roller6 and an adjacent yarn separating guide 62, so that the rollers 6 and 7nip the chain between them. Immediately after passing between therollers 6 and 7 the chain of stitches is unravelled by pulling the yarnfrom the chain and the unravelled yarn engages a motor cut-out device63, which is intended to stop the motor 22 should the yarn break, orshould the tension in the yarn exceed a predetermined limit. Theunravelled yarn then passes around a ceramic guide 64 and through thenip between the rubber surface roller 8 and the roller 9 which are urgedtogether by a spring (not shown) and to be set in the yarn to form aseries of crimps along the which pull the unravelled yarn from the chainof stitches;

axle 41 driven by the motor 22 via pulley 44, belt 45,

pulley 46, pulley 47 and belt 48.

The crimped yarn 13 is fed through a ceramic guide 65- to a yarntraverse guide 66 carried by a reciprocatory Wire forming part of atraverse mechanism and then wound on to take-up bobbin 10, which isdriven by a cork surfaced roller 71. The roller 71 is driven by themotor 22 via pulley 59, belt 61, shaft 72, pulley 47 and belt 48.

In operation, the undrawn yarn 11 is formed into a chain of loopedstitches of the form illustrated in FIG. 4 atthe knitting station. Thetension in the yarn is controlled by the hysteresis tensioner 14. If thetension is too low, the needle 17 is no longer able to form the chain ofstitches. If the tension is too high, the chain moving away from theknitting station tends to pull the undrawn yarn through the knittingstation so that fewer stitches are formed per unit length of the undrawnyarn. Also, when the tension is high the action of the needle'17 cantend to stretch the undrawn yarn and at least partially draw the yarn atthe knitting station.

The tension is adjusted so that the maximum number of stitches areproperly formed in the yarn for a given ratio of the reciprocatory speedof the needle 17 and the throughput speed of the yarn and so that verylittle, if any, drawing takes place at the knitting station.

The chain of looped stitches 12 is fed over the heater by the rollers 3and 4 and the rollers 6 and 7. The peripheral speed of the rollers 6 and7 is arranged to be greater than the peripheral speed of the rollers 3and This causes the chain of looped stitches to be stretched so causingthe stitches to elongate to several times their original length and atthe same time causing the yarn in the stitches to be drawn.

length of the yarn.

Heat may be required to enable the yarn to be drawn as well as to enablecrimps to be set in the yarn. The temperature of the heater is varieddepending on whether or not heat is specifically required for drawingthe yarn and depending on the actual composition and denier of the yarn.

The yarn path between the heater and the rollers 6 and 7 is arranged tobe sufliciently long to allow the yarn to cool while the chain ofstitches is maintained in the stretched configuration.

After leaving the rollers 6 and 7, thelooped stitches are unravelledfrom the leading end of the chain. This is achieved by arranging theperipheral speed of the rollers 8 and 9 to be greater than theperipheral speed of the rollers 6 and 7 in a predetermined ratio. Theratio is chosen so that the unravelling point remains intermediate therollers 6 and 7 and the rollers 8 and 9 as the yarn passes through theapparatus.

The crimped yarn 13 which leaves the rollers ,8 and 9 is wound onto thetake-up bobbin 10. The crimped yarn is substantially uniformly crimped,in the form of a series of uniform waves of V-like shape.

I have found that yarn drawn while in a stitched configuration and heatset in the manner described produces crimped yarn which can be made upinto fabric and satisfactorily dyed inthe usual way.

In one example, undrawn nylon 6 (450 denier, 48 filament) yarn wascrimped in the manner described above. The peripheral speed of therollers 6 and7 was three times greater than the peripheral speed of therollers 3 and 4. The heater temperature was C. The peripheral speed ofthe rollers 8 and 9.was approximately three times that of the rollers 6and 7, and the speed of the crimped yarn onto the take-up bobbin was 280ft./m in. giving a small degree of overfeed on to the package.

It will be appreciated that the type of crimped yarn produced can bevaried in several ways for any particular composition and denier ofyarn. The draw ratio is readily adjustable and can, if desired, beintermittently or regularly adjusted to enable, a non-uniformly crimpedyarn to be produced. The draw ratio is adjusted by altering the relativeperipheral speeds of the rollers 3 and 4 and the rollers 6 and 7.

The frequency at which crimps occur in the crimped yarn is dependent onthe stitch size formed in the undrawn yarn at the knitting station. Thestitch size is .in creased during the drawing of the yarn by apredetermined amount dependent on the draw ratio. Preferably, the stitchsize at the knitting station is kept very small so that the crimpfrequency in the crimped yarn is fairly high.

Instead of forming a chain of stitches as described.

above, the undrawn yarn can be knitted into a length of fabriccomprising a configuration of looped stitches. The length of fabric isthen elongated to several times its length while heatedin order to drawthe yarn in the looped stitches and set the, stitches in their stretchedform to produce, when the fabric is unravelled, a crimped drawn orpartly drawn yarn. I

In some .cases, particularly when crimping multifilament yarn, means maybe provided to increase the three dimensional bulkiness of the crimpedyarn produced. Such means may comprise a sharp edge device or an airblast device arranged to engage or act upon the yarn after it has beenunravelled from the chain and before it is wound on to the package It]and separate the filaments of the yarn to a certain extent.

What is claimed is:

1. A method of drawing and crimping yarn, comprising continuously and onthe run carrying out the following sequence of steps:

(a) forming a drawable yarn into a chain of stitches each of at leastsome of which comprises a segment of yarn passing around the segment ofyarn of another stitch;

(b) feeding said chain to a drawing and setting zone at a first rate;

() passing the chain through the drawing and setting zone;

(d) positively withdrawing said chain from the drawing and setting zoneat a second rate, said second rate being greater than the first ratewhereby the yarn is drawn and at least some of the segments of yarnpassing around other segments of yarn are bent sharply around the othersegments of yarn and the yarn is set in this configuration; and

(e) downstream from said positive withdrawing at said second ratepositively driving said yarn at a third rate, said third rate beingsufficiently greater than said second rate to cause unravelling of thethusly crimped yarn from the leading end of said chain between the pointof said withdrawing at said second rate and the point of said driving atsaid third rate.

2. A method according to claim 1, in which the ratio of said second rateto said first rate is set to equal the desired draw ratio.

3. A method according to claim 1, in which the yarn is heated whilebeing drawn.

4. A method according to claim 3, in which the heated yarn is permittedto cool while drawn.

5. A method according to claim 1, in which each of the stitches of thechain formed in step (21) comprises a segment of yarn passing around thesegment of yarn of another stitch and in step (d) each of the segmentsof yarn passing around other segments of yarn are bent sharply arounothe other segments of yarn and the yarn is set in this configuration.

References Cited ROBERT R. MACKEY, Primary Examiner US. Cl. X.R.

